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Cluster/Conservation Development

Introduction

Over the past fifty years, residential development has spread
across the Illinois landscape, quite rapidly in some areas. As
urbanized areas have grown, people have migrated to what have
become known as “subdivisions” located in more suburban
or rural areas on the outskirts of towns and cities. Much of this
type of development has followed a traditional design, which some
have described as “checkerboard or cookie-cutter housing
development.” The residential zoning ordinances in most
communities have encouraged such traditional designs by requiring
minimum lot sizes, uniform road frontage and lot setbacks, specific
road standards, and other standard requirements. In general, the
only open space within such developments has been the yards between
adjoining privately owned housing lots. In many cases, little
planning went into preserving or improving the quality of the
open-space areas or protecting natural features on the developed
parcel.

As concerns over issues such as “urban sprawl,” open-space
preservation, environmental protection, and farmland loss have
increased, some home buyers, developers, and community officials
have started to question whether the traditional development pattern
provides the quality of life that many homeowners now desire.
To help address these issues, a rather new concept in development,
cluster or conservation design, has become predominant in many
communities. Although still somewhat new to many Midwestern areas,
the cluster designs have been used for some time in parts of the
eastern United States and are beginning to show up in Illinois.

What Is Cluster Development?

The most common name for this new development approach is cluster
development, but conservation design and a number of regional
terms are applied to the same concept. Regardless of its name,
the main objective of cluster development is to allow residential,
or even commercial, development while still protecting the area’s
environmental features, allowing for more open space, and protecting
farmland and the character of rural communities.

Cluster developments differ from traditional developments in
several ways. Cluster developments usually site homes on smaller
lots and there is less emphasis on minimum lot size. However,
the total number of homes, or density, on a given acreage does
not necessarily increase over that allowed in the traditional
subdivision designs. The same number of homes is clustered on
a smaller portion of the total available land. The remaining land,
which would have been allocated to individual home sites, is now
converted into protected open space and shared by the residents
of the subdivision and possibly the entire community. (It is important
to note that there is flexibility on the “homes per land
area” issue: some incentive-based ordinances allow for development
of more homes in exchange for providing other non-required features
that are desirable to the community.)

In most cases, local ordinances and regulations must be updated
to facilitate building conservation development subdivisions.
Road frontages, lot size, setbacks, and other traditional regulations
must be redefined to permit the preservation of environmentally
sensitive areas, rural architecture, historical sites, and other
unique characteristics of the parcel of land being developed.
Developers often cite local regulations as the primary reason
more innovative designs are not used. More flexible regulations
does not mean “anything goes,” however. Traditional
codes must be replaced with new design standards that address
the goals of conservation development, such as open space preservation,
etc.

Open Space Preservation & Maintenance

The increased common open space in cluster developments may be
used for a number of purposes. The specific purposes are defined
during the development’s platting process. In many cases,
the open space is designed to protect natural areas. One principle
of conservation design is that environmentally sensitive areas
must first be identified and designated as non-buildable. Then
subsequent planning can ensure that home lots do not infringe
on those sites and that those sites are not calculated into the
total area permitted for lots. The open space can also be used
for more active recreational facilities, native habitat for wildlife
or plantings, agricultural production, or other allowable purposes.
The landowner and community jointly determine how the open space
will be used while the subdivision proposal is being approved.

In most of these developments, each homeowner has equal access
to the open space areas. In some cases, the open space may be
designed such that the whole community can share its use. Even
if access is limited, the community often shares in the overall
benefits of open-space preservation.

A homeowners’ association is usually responsible for protecting
and maintaining the open space. When necessary, the community
also may have the authority to enforce the open-space provisions
approved in the plat agreement. For example, if necessary maintenance
of open space is being neglected, the community can create a subordinate
special taxing district that taxes homeowners in the subdivision
in order to fund such maintenance.

The open space can also be protected permanently by a conservation
easement, a legally binding agreement that can restrict any unwanted
type of development into perpetuity. (Local U of I Extension offices
have additional information regarding conservation easements.)

Advantages and Disadvantages

As previously suggested, many advantages of cluster development
are related to specific uses of the open space and the “feeling”
that this space generates for a community. Some of the chief advantages
include:

Open space can provide community members with larger recreation
areas and create a sense of openness that many people desire.

Open space can benefit the environment by providing habitat
for wildlife, naturally filtering storm water, reducing storm
water runoff from impervious surfaces, and protecting the natural
features of a site.

Linking the open space of several conservation design subdivisions
can help develop larger and more effective “environmental
corridors” within and between communities.

Developers may benefit because these designs usually reduce
the costs of site development and increase the market price
of individual plots in comparison with traditional subdivisions.

These designs can benefit rural areas by reinforcing the policy
of maintaining the local rural character that is included in
many comprehensive land use plans.

Disadvantages of cluster development may include:

Perhaps most important, local officials, developers, and the
community may be predisposed toward traditional development
designs because they are familiar and well understood. An education
effort may be necessary to help these groups understand the
goals and advantages of cluster development.

During the planning phases, lot and home layout may take extra
work to ensure that while homes are located closer together,
they still take advantage of the open-space goals of the design.

Methods to protect and maintain the open space must be carefully
developed, implemented, and monitored.

Although not necessarily a restricting disadvantage, the
management of waste water must be carefully designed for smaller
lots.

While these disadvantages should be acknowledged and addressed,
none should preclude the use of cluster development.

Waste Water Management

Storm water and septic management can take some additional planning
in a cluster development.

Actually, well-designed cluster developments may benefit the
whole community in terms of storm water management. These developments
usually have less impervious surface cover and provide more open
space for water infiltration. These two factors combined can help
reduce the amount of storm water runoff leaving the property and
thus decrease the chances that the new development will cause
flooding problems. Although traditional subdivisions may be required
to build storm water detention areas, these structures usually
only reduce the flow rate of water, not the increased volume.
Natural areas, such as wetlands or native plantings, that are
a part of the cluster development’s open space can help
manage storm water by reducing the volume of runoff and cleaning
the storm water during the infiltration process. In fact, many
conservation designs include planting deep-rooted native plants
in the open space to help improve soil structure and increase
water infiltration.

Another advantage of cluster developments is that they generally
use less mass grading of the parcel’s soil surface. Such
grading can compact the soil and increase runoff even on areas
where there is no construction. Road ditches in cluster designs
are often grass swales instead of curb and gutter. These grassy
areas allow for more water infiltration and are often less costly
for developers and require less maintenance from the homeowners’
association or community.

Private septic systems in rural areas have always presented a
challenge to communities. It is difficult to ensure proper water
treatment with these systems. The traditional practice has been
to place a septic drain field on an individual homeowner’s
1+ acre lot, assuming the lot meets state and local health requirements.
While this approach may still be possible in a cluster design,
some type of alternative layout or system will probably be required.
Placing easements on the common open space can allow for drain
fields to be established in that area. As technologies improve,
other alternatives, such as mechanical systems, constructed wetlands,
land application, or small community systems, may be used. Local
health departments and the Illinois EPA have additional information
on septic siting and management.

The availability of community sewer systems may help avoid septic
problems when developments are near municipalities.

Does Cluster Development Preserve Farmland?

Putting the same number of houses on less land area can preserve
open space, especially for a subdivision and the adjacent community.
Does it preserve land for agricultural purposes? That question
is not as easy to answer.

Some cluster developments, especially large ones, can preserve
open space for agriculture. The open area may be leased to farmers
for typical Midwestern farming practices. Alternatively, the homeowners
can plant community gardens or engage in small-scale agricultural
production. In some cases, the open space could even house livestock,
such as horses, owned by the homeowners or others.

However, unless the open space is a large acreage, it may be
difficult for traditional farming to continue in the open-space
areas. Traffic congestion, crop damage, farm noise, odors, etc.,
all discourage many farmers from farming such parcels of land
around subdivisions, especially in rapidly developing areas. Even
so, the open space in cluster developments can provide a good
buffer between traditional farming operations and residential
areas, thus alleviating some of the pressures of neighboring development
and allowing farming to continue in nearby areas longer into the
future.

This material written by John Church, Extension Educator, Natural Resources
Management, University of Illinois. Reviewed by Gerrit Knaap, Associate
Professor, Urban and Regional Planning, University of Illinois College
of Fine and Applied Arts